tbuckley/cabot-search huggingface dataset:
P20.14.B SYSTEMIC THERAPY FOR RECURRENT ADULT INTRACRANIAL AND SPINAL EPENDYMOMAS: A MONO-INSTITUTIONAL EXPERIENCE
Authors: M Maccari, M Padovan, M Caccese, G Cerretti, G Lombardi
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Ependymoma is a rare disease in adult patients (pts) and there is no standard systemic treatment in recurrent disease after surgery and radiotherapy. We reviewed our cases of confirmed intracranial and spinal ependymomas and described experience of pts treated with systemic therapies at disease recurrence. MATERIAL AND METHODS We retrospectively collected data of pts with histopathologically confirmed intracranial and spinal ependymomas from Veneto Institute of Oncology IOV in Padua, Italy from April 2018 to April 2023 and identified a subgroup of pts that received at least one line of systemic therapy at disease recurrence. All ependymomas were classified according to WHO 2016. As local protocol, brain and spinal MRI was performed every 2-3 months or when clinically indicated. RANO criteria were used to neuroradiological response. Primary endpoints were disease control rate and progression-free survival. RESULTS A total of 36 adult pts with ependymoma were identified, 18 males, median age at diagnosis 43. Tumor locations were spine (n=6), infratentorial (n=6), supratentorial (n=24). The majority were grade 3 (n=15), the others grade 2 (n=11) and grade 1 ependymoma (n=10).9 selected pts received at least one line of systemic treatments at disease recurrence (6 female, 3 male, median age at diagnosis 42 years). The majority were grade 3 (n=7), the others grade 2 (n=2). All 9 pts had undergone surgery and adjuvant radiotherapy. In this subgroup, the median time to recurrence from diagnosis was 12.4 months (range 3-32). At disease recurrence surgery was re-performed in 3 pts. Median number of lines of systemic therapies was 2, with a range from 1 to 6. TMZ alone in 4 pts with a DCR 40% and mPFS 4ms; TMZ+ cisplatin in 2 pts (DCR 50%, mPFS 4ms); TMZ+lapatinib in 3 pts (DCR 33%, mPFS 3.5ms); TMZ+bevacizumab in 1 pt (DCR 0%, mPFS 2ms); bevacizumab alone in 2 pts (DCR 0%, mPFS 2ms); bevacizumab+fotemustine in 1 pts (DCR 100%, mPFS 14ms), fotemustine alone in 2 pts (DCR 50%, mPFS 7.5ms); carboplatin 1 pts (DCR 0%, mPFS 2ms). At the data cut-off (April 2023), median overall survival from the date of diagnosis was 18.5 months (range 2-50). CONCLUSION The management of recurrent ependymoma in adults remains a therapeutic challenge. Our experience reflects heterogeneity regarding systemic treatments for patients with more aggressive ependymomas. Even if it was a small population, TMZ plus cisplatin ,fotemustine alone or in association with bevacizumab might represent promising treatments. However, other larger and prospective studies are needed.
P06.02.B GSDME-MEDIATED PYROPTOSIS IN GLIOBLASTOMA
Authors: E Solel, E Brudvik, S Afroz, R Choudhury, R Bjerkvig, J Hossain, H Miletic
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Immunotherapeutic strategies have largely failed for glioblastoma , the most frequent primary brain tumor. Beyond apoptosis and autophagy, little is known about cell death mechanisms in glioblastoma, despite their potential impact on the immune microenvironment. Pyroptosis, unlike apoptosis, is an immunogenic and lytic type of programmed cell death, where gasdermin proteins form pores into the plasma membrane, releasing cell content to the tumor microenvironment. Gasdermin E (GSDME), often inactivated in cancers by mutations/low expression, is proteolytically cleaved by caspase-3 upon apoptotic stimuli leading to a shift from apoptosis to pyroptosis. Here, we investigated the relevance of GSDME-mediated pyroptosis for glioblastoma. According to The Cancer Genome Atlas, GSDME is highly expressed in glioblastomas compared to many other cancers and no mutations are found. MATERIAL AND METHODS Using the drug raptinal to induce apoptosis, we assessed expression of full length and cleaved GSDME as well as cleaved caspase-3 in syngeneic mouse and human patient-derived glioblastoma stem-like cell lines by western blotting. Lytic cell death and viability were measured by lactate dehydrogenase (LDH) and WST-1 assays respectively. PI uptake assay was performed to capture pyroptotic morphology by Incucyte®️ S3. BAPTA-AM, a fast Ca2+ chelator, was used to block plasma membrane repair in human glioblastoma cell lines and analyze its effect on pyroptosis. GSDME was knocked out by CRISPR/Cas9. RESULTS GSDME and caspase-3 cleavage were confirmed after raptinal treatment in mouse and human glioblastoma cell lines, indicating that the molecular pyroptotic machinery is intact. A significant drop in viability with raptinal was shown indicating successful execution of cell death. A significant LDH release was detected in mouse glioblastoma cell lines, which could be blocked by GSDME knockout. In contrast, human glioblastoma cells, although executing GSDME cleavage, showed less or no LDH release. Pyroptotic morphology was detected after raptinal treatment in mouse glioblastoma cell lines, while it was delayed/inhibited in human glioblastoma cells. Application of BAPTA-AM in human glioblastoma cell lines enhanced pyroptotic morphology, indicating a role for plasma membrane repair in inhibiting pyroptosis. CONCLUSION The molecular machinery to execute pyroptosis is functioning in mouse and human glioblastoma cells. However, while mouse glioblastoma cells show clear execution of pyroptosis upon apoptosis induction, human glioblastoma cells indicate less efficient pyroptotic ability which partly can be reverted by blocking plasma membrane repair. While pyroptosis can induce anti-tumor immunity in experimental cancer models, future in vivo experiments must delineate if pyroptosis is a viable strategy for immunotherapy of glioblastoma.
P17.15.A THANK PHASE I TRIAL OF DNX-2440 ONCOLYTIC ADENOVIRUS IN PATIENTS WITH FIRST OR SECOND RECURRENCE OF GLIOBLASTOMA: PRELIMINARY RESULTS
Authors: J Gallego Perez-Larraya, D de la Nava, M González-Huárriz, M García-Moure, S Labiano, M Zalacaín, L Marrodán, I Ausejo, V Laspidea, I Hervás, M Puigdelloses, I Esparragosa, M Giráldez, M Serrano, P Domínguez, R Díez-Valle, J Fueyo, C Gomez-Manzano, A Patiño, S Tejada, B Bejarano, M Alonso
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Oncolytic immunovirotherapy is emerging as a potential therapeutic approach in neuro-oncology. The oncolytic adenovirus DNX-2401, genetically engineered for selective replication and enhanced infectivity in tumor cells, has shown efficacy in adult patients with recurrent glioblastoma (GBM). In order to overcome the immunosuppressive brain-tumor microenvironment and thus enhance its antiglioma effect, DNX-2440 is a new armed virus which contains the same modifications but additionally incorporates OX40 ligand to induce the expression of such molecule in tumor cells and so increase the antitumor immune response. MATERIAL AND METHODS We are conducting a phase I open-label single-center study to investigate the safety and efficacy of a single intratumoral injection of DNX-2440 in patients with first or second recurrence of GBM. This is a dose escalation study, with a 3 + 3 design, evaluating an initial dose of 4x10e9 viral particles (vp) and a target dose of 4x10e10 vp. A single measurable lesion bigger than 10 mm in two perpendicular diameters and smaller than 25 cc is required for inclusion in the study. RESULTS To date 16 patients (6 [37.5%] female, 10 [62.5%] male) have been enrolled and treated with DNX-2401. Median age is 55 years (range, 39-80) and median KPS is 80 (range 70-90). As per protocol, surgery consisted of biopsy in all patients followed by intratumoral injection of DNX-2440. No dose limiting toxicity has been registered during the dose escalation phase (first cohort of 3 patients receiving 4x10e9 vp, and second cohort of 3 patients receiving 4x10e10 vp), and the remainder patients have received the target dose of 4x10e10 vp in the dose expansion cohort. Safety profile is acceptable with no serious adverse events related to DNX-2440 reported to date. Clinical benefit with tumor size reduction and prolonged survival have already been confirmed in 3 patients. Correlative analyses evaluating immune response in blood samples are ongoing. CONCLUSION Our current data suggest that intratumoral injection of DNX-2440 is feasible and safe, and seems to provide a clinical benefit in some patients with recurrent GBM. Furthermore, this trial illustrates the potential of oncolytic virus platforms to reshape the brain-tumor microenvironment and its interesting role in combination strategies with other immune-oncology agents for treating this disease.
P10.25.A ATR INHIBITION IN EXPERIMENTAL GLIOMA: DISCOVERY AND VALIDATION OF MOLECULAR TARGETS FOR FUNCTIONALLY-INSTRUCTED COMBINATION THERAPIES
Authors: B Walter, S Hirsch, L Kuhlburger, A Stahl, L Schnabel, L A Haeusser, F Tsiami, S Ploeger, N Aghaallaei, A M Dick, J Skokowa, C Schmees, M Templin, K Schenke-Layland, M Tatagiba, S Nahnsen, D Merk, G Tabatabai
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND The DNA damage response (DDR) is an important physiological network for the prevention of malignant transformation, e.g. by halting the cell cycle upon DNA damage detection and promoting DNA repair. Glioblastoma are incurable primary brain tumors that display acquired treatment resistance which might also be due to DDR dysregulation. Furthermore, we had recently investigated molecular effects of disrupting the (b)HLH network, a frequently altered and tumor-promoting transcriptional network in glioma. The identified downstream anti-tumor effects included the ataxia telangiectasia and Rad3 related (ATR) pathway. In the present study, we aimed at investigating the anti-glioma effects of ATR inhibition (ATRi) in experimental glioma and exploring potential treatment regimens for forward translation. MATERIAL AND METHODS We assessed ATRi monotherapy in the syngeneic SMA560/VM/Dk mouse model, performed acute cytotoxicity, clonogenic survival assays, cell cycle analyses by flow cytometry and apoptosis induction in vitro. Furthermore, we used RNA sequencing, DigiWest protein profiling analyses and genome-wide CRISPR/Cas9 loss-of function and activation screens. We evaluated synergistic or additive anti-glioma effects of functionally-instructed combination therapies by the Bliss and ZIP synergy models. We xenotransplanted zebrafish embryos with glioma cells to validate most promising combination approaches in vivo. RESULTS ATRi monotherapy induced prolonged latency until the onset of neurological symptoms in the SMA560/VM/Dk mouse model. ATRi reduced viability and clonogenic survival in vitro and ex vivo. Molecular analyses revealed differential patterns of gene expression, e.g. p53 signaling, differing modes of cell cycle and apoptosis regulation, arguing for a profound context specificity of the treatment. Similarly, CRISPR/Cas-9 genome-wide knockout and activation screens revealed distinct genetic vulnerabilities. Based on these RESULTS , we designed a drug library for investigating potential functionally-instructed modifiers of response to ATRi in experimental glioma in vitro, ex vivo and in vivo. CONCLUSION In summary, we present a workflow in experimental glioma for target discovery and validation leading to the design of novel combination therapies. We identify potential combination therapies involving ATRi in experimental glioma that could inform future early phase clinical trials and preclinical studies.
P12.04.B MGMT-STATUS OF TUMOR INFILTRATING MACROPHAGES IN HUMAN GLIOBLASTOMA
Authors: A Zeiler, F Liesche-Starnecker, C Delbridge, A Wagner, J Gempt, J Schlegel
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastomas are the most prevalent malignant brain tumors in adults, with a frequency ranging from 0.59 to 3.69 in the western world. They are accompanied by a fatal prognosis and a median survival of 12.2 to 18.2 months. Their significant intratumoral and intertumoral heterogeneity is the reason for this. Tumor associated macrophages including microglia can represent up to 30-40% of the cellular component of the tumor and are thought to have an impact on the tumor's behavior. The MGMT promotor methylation is the most significant clinical prognostic factor. Patients with a methylated promotor have a better prognosis and a better response to Temozolomid treatment. This experimental study should determine if the microglia or the tumor cells are responsible for the MGMT status. Moreover, it should show how the MGMT-protein is distributed intracellularly in both cell-populations. MATERIAL AND METHODS Therefore, the MGMT-Status of 13 samples of patients with glioblastoma from the division of neurosurgery of the TU München were analyzed. Using magnetic cell sorting and an anti-CD11b antibody, tumor cells and microglia were separated in each sample. A MGMT-assay was carried out for each cell population to demonstrate the proportion of methylated MGMT promotor regions. 25 histological sections underwent immunofluoresence double staining to get a better look at the MGMT protein's intracellular distribution. Two sections of each sample were stained with anti-MGMT antibody and anti-GFAP antibody or anti-IBA1 antibody, respectively, to determine if the MGMT protein is present either in the nucleus or in the cytoplasm of the tumor cells and microglia. A minimum of 200 cells of every section was analyzed manually. Statistical analysis was performed using Mann-Whitney-U-test and a p-value &amp;lt;0.05 was defined as significant. RESULTS The separarte MGMT-assay of microglia and tumor cells showed methylated MGMT promotors in 3 samples in both cell populations. Tumor cells as well as microglia demonstrated intracellular MGMT Protein, with no significant difference (0.122 MGMT+ Microglia vs. 0.152 MGMT+ Tumor Cells; p=0.101). The intracellular distribution of the MGMT protein strengthened this result. Tumor cells demonstrated a significantly higher percentage of nuclear MGMT protein (0.602 nuclear MGMT vs. 0.203 cytoplasmic MGMT; p&amp;lt;0.0001), whereas microglial cells showed a significantly higher expression of cytoplasmic MGMT protein (0.608 cytoplasmic MGMT vs. 0.157 nuclear MGMT; p&amp;lt;0.0001). CONCLUSION According to the findings of this experimental study, both the microglia and the tumor cells are responsible for the clinical MGMT status. This might fit into the theory of macrophage polarization in the microenvironment of heterogenous tumors. The MGMT protein distribution pattern implies that tumor cells and microglia express their MGMT protein in different cellular compartments.
P19.02.A FUNCTIONAL CONSEQUENCES OF IDH1 AND CIC MUTATIONS ON OLIGODENDROGLIOMA CELLS OF ORIGIN
Authors: N Pottier, S Joppé, N Magne, S Paris, L Delannoy, C Bardella, E Huillard
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Oligodendrogliomas are primitive tumors of the central nervous system characterized by mutations in isocitrate dehydrogenase 1 (IDH1R132H) gene, codeletion of 1p and 19q chromosomic arms and mutations in Capicua (CIC) gene. Oligodendrocyte precursor cells (OPCs) are potential cells of origin for oligodendrogliomas and OPC-like tumor cells are responsible for tumor amplification at early stages of gliomagenesis. Although genetic alterations are well characterized for these tumors, little is known about the roles of IDH1 and CIC in oligodendroglioma initiation and development. Individually, IDH1 and CIC mutations can induce neoplastic characteristics but are not sufficient for tumoral development. We aim to understand how IDH1 and CIC mutations impact OPC development and whether these alterations are sufficient for tumoral initiation. METHODS We have generated an inducible mouse model allowing endogenous expression of IDH1R132H and inactivation of CIC in postnatal OPCs. We analyzed by immunofluorescence the proliferation and differentiation status of mutated oligodendroglial cells and other brain cells, at postnatal and adult stages. RESULTS We describe distinct effects of these mutations on oligodendroglial cell number and proliferation, at early and late time points. In addition, we found that IDH1R132H increases the proliferation of other brain cell types, suggesting paracrine effects of this mutation in the brain. We find no evidence of tumor in the brain of mice mutated for both IDH1 and CIC at late time points. CONCLUSION Our study describes for the first time the phenotypic impact of the combined expression of IDH1 and CIC mutations on oligodendroglial lineage cells and other brain cells, leading to a better understanding of oligodendroglioma development.
P02.10.B REGULATION OF GLIOBLASTOMA CANCER STEM CELLS AND PROLIFERATION THROUGH VOLTAGE GATED SODIUM CHANNEL
Authors: F Brandalise, F Cianci, C Biella, E Pastorelli, F Giammello, M Amat di San Filippo, M Mazzanti
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastoma Multiforme (GBM) is one of the most devastating cancer known. Despite decades of research, we still lack an efficient treatment. The heterogeneity in the cell-type composition along with the presence of a subpopulation of cells with high tumorigenic capacity named glioblastoma stem cells (GSCs), make GBM extremely hard to treat. An extensive body of works supports the hypothesis that an aberrant functional expression of membrane ion channels mediates the progression of solid cancer tumors. Potassium, calcium, and chloride channels have been largely correlated with carcinogenesis. However, little is known about the voltage-gated-sodium channel (Nav) in GBM. In fact, the role of this membrane ionic permeability in the GBM progression and relapse is yet to be unveiled. MATERIAL AND METHODS Experiments have been performed on human GSCs obtained from surgical specimen at the Neurosurgery Department of IRCCS-AOU San Marino IST (Genova, Italy), from patients who had not received therapies before intervention. The mRNA profile of the cell lines as well as the transcript expression of stemness markers were evaluated both in control condition and in the presence of the Nav channel blocker Tetrodotoxin (TTX, 30μM). The protein content for the stemness markers and their intermediates was quantified using Western-Blot analysis. Nav-mediated inward currents were recorded from single cells and measured in voltage clamp by applying consecutive voltage steps of +10 mV from a holding potential of -70 mV and up to +60 mV. Transient inward current was calculated on the peak subtracting the baseline leak currents. Current density (pA/pF) was calculated as the ratio between the peak current recorded at +20 mV and the capacitance of the cell. Resting membrane potential (RMP) was also assessed in each recorded cells. RESULTS We have identified a subpopulation of GBM cells (in GBM Proneuronal subtype) that functionally expressed TTX-sensitive inward currents. Transcriptomics investigation reveals the significant expression of SCN1A mRNA. We have shown that Nav density positively correlates with the RMP in GBM cells. Additionally, Nav blockade promotes glioma cell proliferation and G1/S accumulation. Pharmacological blockade of Nav-mediated currents has shown a significant impact on some stemness markers both at the mRNA and protein expression level. A regulatory downstream pathway, modulated by Nav has also been investigated. CONCLUSION Our evidences suggests that Nav-mediated currents is significantly expressed in a subpopulation of GBM cells. As a result, the present study intends to demonstrate how Nav plays a fundamental role during GBM progression and correlates with the tumor resistance to treatments.
P11.70.A EQUITY IN GENOMIC TESTING: LESSONS LEARNT FOLLOWING THE ROLLOUT OF AN AMBITIOUS GENOMIC TESTING STRATEGY FOR NEUROLOGICAL TUMOUR PATIENTS IN THE UNITED KINGDOM
Authors: N Huskens, C Aitken, C Watts, K Kurian
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND The NHS England Genomic Test Directory now offers extensive genomic testing to brain tumour patients including whole genome sequencing (WGS), methylation arrays, gene panels, and other targeted mutation tests. Comprehensive genomic testing enables precise diagnosis and prognosis, tailoring of treatment, and research into new actionable targets. Despite the ambitious plans and potential for significant patient benefits, the Tessa Jowell Brain Cancer Mission (TJBCM) identified variation in deployment of these tests across Neuro-Oncology Centres in the UK. Based on these findings, we aimed to further understand the variation. We aimed to uncover drivers to delivering a successful genomic testing programme and identify local and national barriers to rolling out extensive genomic testing. MATERIAL AND METHODS As part of the TJBCM Centre of Excellence Programme, 90% of Neuro-Oncology Centres in the UK provided self-reported data on volumes of genomic testing for brain tumour patients. Subsequently, structured interviews were conducted with neuro-oncologists, neuropathologists, neurosurgeons, clinical scientists and other stakeholders from these Centres to further evaluate the state of genomic testing. RESULTS Accessibility to WGS varied from no access, to Centres where WGS was available in a limited capacity, to Centres where WGS was accessible but not scalable or timely. Bottlenecks were identified throughout the WGS pathway including inadequate tumour tissue, sample processing and transport delays, and insufficient clinical scientists to interpret results. As such, no UK Centre interviewed had sufficient capacity to offer WGS to all neurological tumour patients in a timely manner using NHS-accredited pathways. Interviews showed geographic variability in access to basic molecular tests such as methylation array and CDKN2A/B which are required for diagnostics and prognostics. There was also a strong reliance on a small number of laboratories to provide methylation array, resulting in backlogs. Common drivers to effective delivery of genomic testing included funded posts for research nurses, innovative systems for delivery of tumour samples from surgery to the laboratory, dedicated staff who advocated for genomic testing, and well-established Genomic Tumour Advisory Boards for test interpretation. CONCLUSION Impressive progress has been made in the last two years yet there remains a mismatch between what the National Genomic Test Directory dictates, and what can currently be delivered in a manageable timeframe. Inconsistencies in infrastructure, funding and training are preventing UK Centres from delivering the intended world-leading genomic testing. Barriers to address vary from simple changes at a local level, to national coordination and funding so that genomic testing will be equally accessible to all brain tumour patients in the UK.